Kuro and Rogue

The two immediately went down to help Raiden once they were informed. Rogue used her Earth Manipulation like Beast as well as Fire Manipulation to burn through the rubble while Kuro shapeshifted into Rogue and did the same. Within a few hours, they managed to get down into the main room, although it was still covered in rubble. It was still going to take a while until the cleared everything out. Rogue stopped and turned to everyone with a yawn.

"I think it would be best to stop for the night. We need our rest, if we use all our energy digging through this, and are invaded tomorrow, we won't be able to fight, and this room is large, there is a lot of rubble, a lot of work to be done."

She turned to the room and sighed, it wasn't even half done yet. 

Terraci

Terraci suddenly appeared in front of everyone. He looked up and shook his head. It seemed he was back, and his face was grim. It was a face which bared a hefty secret, one filled with bad news. He looked to the room, full of rubble, then turned back to the chief.

"Wise and old, the prophet is back. The man is blind, the man is strong. Through songs and cheers, a leader was born. Younger and not as wise, the man acted. Frightened and unwise. Sent far below, the wicked witch, where crystal lied. Held secret from generations, untold legends. Nobody knew, nobody believed. Years passed, and the leader died, they believed. The leader cheated, surpassing strongest of forces, but came a price. Leader had to believe, accepted, he finally did in that which he never thought possible. He had to hide, he had to lie. Protecting himself later generations, the next kings and queens. Deep below, a secret room, prisons and jails, now arena which held above. Deep below, a secret room, empty, the witch great and powerful, escaped. Book of secrets, book of history, read many times, secrets of crystal inside. Now he knew, now he feared. Searched many years, missing, gone, the crystal was, no, hidden all along, least expected, deep within. Under Berk once before, now above forever more. Odin's statue, royal guard, protector of cells. Held a gem, not any more. Kept secret, crystal great and powerful. Had no choice, hidden all along, future kings and queens, Berk, least expected. Home of Kings, home of Queens, home of young prince, wars end, thanks to him, prince of queen today. Unknown secret lies within, hidden room. The past I speak, the present I talk. Future, I am blind."

He then disappeared, vanished into thin air. 

Morrigan

Morrigan looked to the moon and smiled, it was time. She transformed back and laughed evilly. She was surprised that nobody was out protecting the place. She burnt a hole through the ground and jumped down, quickly landing above the hidden room, now she was annoyed! They collapsed everything. She growled angrily, it would take too much time, she needed to get to the crystal!